肾集合管癌的CT和MRI表现

CT and MRI findings of the kidney collecting duct carcinoma

目的分析肾脏集合管癌的CT和MRI表现特点,以提高对该病的认识。方法回顾性分析8例经手术病理证实的肾脏集合管癌的CT及MRI表现。结果病灶全部为单肾发病,左肾6例,右肾2例。肿块直径1.5～12cm,平均7.2cm。肿块实质性3例,其余5例均为囊实性,2例见钙化。CT平扫病灶等低密度混杂不均匀,MRI T1WI等低信号,T2WI高低混杂信号;CT和MRI增强表现为不均匀低或轻度延时强化,呈浸润性生长;易侵犯肾窦及肾周,其中1例包绕主动脉,左侧肾上腺受累2例,脾脏及后腹膜、肠系膜根部受累者各1例,后腹膜淋巴结肿大融合3例,肾静脉及下腔静脉癌栓1例。结论肾脏集合管癌CT和MRI表现具有一定的特点,因其恶性程度高,愈后较差,术前具有鉴别诊断的意义。

Objective We characterized CT and MRI findings of the kidney collecting duct carcinoma （CDC） in order to improve the understanding of this disease. Methods CT and MRI findings of 8 CDCs proved by post-operation pathology were retrospectively reviewed. Results All of 8 cases were unilateral and solitary, involvement left kidney with 6 cases and right kidney with 2 cases. The tumors varied in size from 1.5 to 12 cm （mean, 7.2 cm）. The lesions appeared solid （3/8） or complex solid and cystic （5/8） on CT. Calcification was found in 2 cases. Unenhanced CT scan showed heterogeneous iso hypodense attenuation compared with that of normal parenchyma. The solid tumor component was iso hypointensity on T1-weighted spin echo MR images and hypointensity on T2 weighted spin-echo MR images to normal renal parenchyma. After IV contrast administration, heterogeneous minimal degree delayed enhancement was present both on CT and MR images. CT and MR imaging appeared an infiltrative pattern of tumor growth. The involvement of the renal sinus and perirenal space were common. The aorta encompassed by tumor was present in one case. The left-side adrenal metastasis was seen in 3 cases. Regional retroperitoneum lymphadenopathy with coalescent nodal masses was seen in 3 cases. Tumor thrombosis was seen in the renal vein and in the inferior vena cava in one case. Conclusion On CT and MR images, some specific findings were frequently seen in patients with CDC. These findings are well correlated with highly malignant and poor prognosis of this disease. Thus, the CT and MR features are very significant for the preoperative differential diagnosis of this disease.